Comment 29 for bug 177713

Hi guys, I had same problem with CFS + BOINC + pulseaudio on my Pentium 4 HT 2.8GHz. The trouble was caused by using schedtool to run BOINC. After I removed it (sudo aptitude purge schedtool), there was no pulseaudio stuttering (despite pulseaudio is using 20% of my CPU... which is IMHO pretty high). This bug is 100% reproducible on Debian with 2.6.26 kernels. I have default pulseadio config (and changed only number of default-output-channels from 2 to 6), and while listening to music (running audacious audio player with pulse output), and running BOINC at the same time I have no stuttering. Then if I install schedtool (sudo aptitude install schedtool) and restart BOINC (sudo /etc/init.d/boinc-client restart) the music starts to lag, skip etc... then removing schedool (sudo aptitude purge schedtool) and restarting BOINC again makes the music run fine (e.g. no stuttering and skips).
I'm not 100% sure this will help you guys with Ubuntu systems, but since Debian and Ubuntu are pretty close, I think it could be the same problem...
Schedtool isn't installed by default on Debian(same for Ubuntu), but it happened that I used it to run BOINC, before 2.6.24 kernel with CFS was released...

PS: this bug isn't related to CONFIG_FAIR_USER_SCHED, where all users have same priority and it slows systems with BOINC running, because BOINC is running under boinc user, which has 50% of CPU share. It's for those who got sound issues, even after using kernels with CONFIG_FAIR_USER_SCHED turned off...